The present invention relates to a tire/wheel assembly which enables run-flat traveling and to a run-flat support member which is employed in the tire/wheel assembly. More specifically, the present invention relates to a tire/wheel assembly and a run-flat support member in which durability is improved for run-flat traveling.
To meet the demand from the market, numerous techniques have been proposed to enable a certain degree of emergency driving even when a pneumatic tire is punctured while driving a vehicle. Among those numerous proposals, the techniques proposed in Japanese Patent Laid-Open Publication No. 10-297226 and Published Japanese Translation of a PCT Application No. 2001-519279 enable run-flat traveling by fitting a core to a rim in a cavity of a pneumatic tire assembled to the rim and supporting a flat tire with the core.
The foregoing run-flat core has an open-leg-structured circular shell including a support surface thereof extended toward the periphery of the tire and leg portions along each side of the support surface. The run-flat core is constituted by attaching elastic rings to both of these leg portions so that the core is supported on the rim through the elastic rings. The advantage of the run-flat core is that the available rims and wheels in the market can be used as their own, without any particular modifications. Thus, the core can be accepted to the market without causing difficulties therein.
Nevertheless, in a tire/wheel assembly including the preceding core, large stresses act on bonding portions between the elastic rings and the leg portions of the circular shell during run-flat traveling. Accordingly, there has been a problem that durability required for run-flat traveling cannot be satisfied when adhesion is insufficient between the elastic rings and leg portions of the circular shell. To counteract the problem, for example, it is considered that surfaces of the leg portions of the circular shell, which are bonded with the elastic rings, are made rough. However, these rough surfaces could not sufficiently improve the adhesion between the two.